In this paper we intend to design a reduced ultrawideband band-pass filter using new models of coupled transmission lines. In this paper, by providing a new model of resonators, the bandwidth of band-pass filters (which are among the most crucial elements in communication systems) will be moderately increased, while their size and volume decreases. According to the change of their equations and consequent changes in basic parameters of these models, optimization and dependency among these parameters and also the frequency response of these filters will be developed to utilize notches in the pass-band, and a reduced ultrawideband band-pass filter with notch will be designed and analyzed.